I found these period photos on Dick Stockton's "the 71 Crowd" Facebook page. Thanks to Scott Adams and Dick for posting.

I understand there were two alloy bodied Mk.IV cars. I believe Dick drove 100/70 in 1960-62, after Chuck Dietrich ran it in England.
There is some question, as Dick told me the car was natural alloy when he bought it, no sign of paint. Dietrich's car was green, so perhaps Chuck ran "Puddle Jumper" alloy 100/69.

You'll see the natural alloy body wrinkled, dark primed, then silver again (painted?)

It was sold, raced and wrecked at the last Put-in-Bay 1963. Sold to Jon Clifton in 1965.

Very real personality, the guy you should write a book about. No silver spoon gentleman racer, but a mechanic that prepped his own rides, and there were some interesting cars out of his Havertown,PA shop.

If you go to the FB site there are pics of the cars Dick has raced; hotrod Fords, Healey/Chev, Ferrari, Lister, F5000, Cobra, and TR4 besides the alloy Mk.IV.
In the '70s he had an IMSA sedan that also got wrinkled. Dick is still involved with the Kyle Disque GTL Toyota effort.